Photoisomerization of Cyclopropane Derivatives. Photointerconversion of Propenes and Cyclopropanes

Griffin, G. W.; Covell, J.; Petterson, R. C.; Dodson, R. M.; Klose, G.

doi:10.1021/ja01084a066

Cited by 75 publications

(37 citation statements)

References 1 publication

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“…The same product ratio was obtained by irradiation of each of the pure isomers 9 c and 10 c respectively. Obviously, aryl‐substituted benzoylcyclopropanes undergo photochemical cis – trans isomerization, probably through an intramolecular charge transfer 10…”

Section: Methodsmentioning

confidence: 99%

Novel functional polymers: Poly(dimethyl siloxane)–polyamide multiblock copolymers. XI. The effects of sequence regularity on the thermal and mechanical properties

Kang

Kaneko

Shiino

et al. 2003

J. Polym. Sci. A Polym. Chem.

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Poly(aramid silicone) (PAS) multiblock copolymers were synthesized by the low‐temperature solution polycondensation of isophthaloyl dichloride (IPC) and two diamines, diamino poly(dimethyl siloxane) (PDMS; number‐average molecular weight = 1680) and 3,4′‐diaminodiphenylether (3,4′‐DAPE), in tetrahydrofuran/dimethylacetamide (2/1 v/v). Two synthetic methods for the control of the PAS sequence were used: a one‐step synthesis that presumably gave PAS with a random sequence and the polymerization of 3,4′‐DAPE with a presynthesized dimer, IPC–PDMS–IPC (two‐step synthesis), that presumably gave PAS with an alternating sequence of 3,4′‐DAPE and PDMS segments. In a 1H NMR study of the amide protons of the 3,4′‐DAPE component in PAS, the relative length of the 3,4′‐DAPE segment of randomly sequenced PAS to that of ideally sequenced PAS could be estimated. The glass‐transition temperatures of the 3,4′‐DAPE and PDMS segments of random PAS were 152–234 and −104 to −117 °C, respectively, whereas the alternating PAS sequences showed no glass transition for the 3,4′‐DAPE segments. A tensile test indicated that randomly sequenced PAS behaved like a rubber‐toughened material at lower PDMS contents and like a thermoplastic elastomer at higher PDMS contents, whereas the alternately sequenced PAS behaved like a very soft rubber, showing a high value of elongation at the breaking point. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 841–852, 2003

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Section: Methodsmentioning

confidence: 99%

Novel functional polymers: Poly(dimethyl siloxane)–polyamide multiblock copolymers. XI. The effects of sequence regularity on the thermal and mechanical properties

Kang

Kaneko

Shiino

et al. 2003

J. Polym. Sci. A Polym. Chem.

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“…light (Rayonet reactor with mercury low-pressure lamps, 40°) produced a 0.65 ratio of 47:48 [50]. light (Rayonet reactor with mercury low-pressure lamps, 40°) produced a 0.65 ratio of 47:48 [50].…”

Section: Photochemical Cis-trans Isomerizations Of Cyclopropane and Cmentioning

confidence: 99%

Photochemical stereoisomerization

Schönberg¹

1968

Preparative Organic Photochemistry

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“…Also, the lowest rearrangement products of the 1,l-dimetllyl antibonding orbitals of benzene have nearly the derivative could be found, nor could evidence same energy (-1.00P) as $6 of the indeny1 for hydrogen migration in indene be produced. radical (-0.90P) (18) hence the overlap will The low migratory aptitudes of hydrogen and cause a significant energy lowering in the transimethyl relative to phenyl callnot be an inherent tion state, resulting in the facile migration of a quality in the former two, since all three groups phenyl group.5 migrate readily in other systems (13)(14)(15)(16).…”

Section: Mechanistic Aspectsmentioning

confidence: 99%

Photochemical rearrangement and dimerization of 1,1-disubstituted indenes

McCullough¹

1968

Can. J. Chem.

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The pliotochemical behavior of 1,l-diphenylindene and 1,l-dimethylindene has been studied. The fornicr undergoes efficient rearrangement on direct irradiation or on acetophenone sensitization, forming 2,3-diphenylindene and 1 ,Zdiphenylindene. In contrast, 1,l-dimethylindene gave n o detectable products of methyl migration but formed dimeric cyclobutanes on scnsitized and direct photolysis. The structures of thc two dimers formed in the sensitized reaction were assigned from their nuclear magnetic resonance spectra. It was also demonstrated that hydrogen, like methyl, migrated inefficiently if at all in this system. This difference in migrato~y aptitudes is discussed in terms of orbital symmetry of the indene system.

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Photoisomerization of Cyclopropane Derivatives. Photointerconversion of Propenes and Cyclopropanes

Cited by 75 publications

References 1 publication

Novel functional polymers: Poly(dimethyl siloxane)–polyamide multiblock copolymers. XI. The effects of sequence regularity on the thermal and mechanical properties

Novel functional polymers: Poly(dimethyl siloxane)–polyamide multiblock copolymers. XI. The effects of sequence regularity on the thermal and mechanical properties

Photochemical stereoisomerization

Photochemical rearrangement and dimerization of 1,1-disubstituted indenes

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